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G78R

Category 5 — IDR ExclusionConflictingCytoplasmic · predictedEditorial
GlycineArginine at position 78 · N-terminal intrinsically disordered region (1-86) · WFS1 (Wolframin)

Glycine → Arginine at position 78 in wolframin's N-terminal intrinsically disordered region (IDR). ClinVar carries conflicting classifications. AlphaMissense 0.106 (likely BENIGN by AM, not pathogenic). pLDDT 26 — deep IDR. DynaMut2 ΔΔG -0.48 kcal/mol but NOT trustworthy in this region. A Category 5 IDR variant that requires wet-lab characterization.

Interactive 3D Structure

Wild-type reference
Wild-type G78 — hydrogen bond to T80
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DynaMut2 mutant · G78R
Mutant R78 — van der waals contact to T80 lost
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Bond changes · DynaMut2 interaction analysis

1 lost0 gained2 preserved
Interaction typeWild-type partnerMutant partnerStatus
Hydrogen bondT80T80Preserved
Polar contactT80T80Preserved
Van der WaalsT80Lost

Lost / gained / preserved interatomic contacts at the variant residue, from the DynaMut2 (Arpeggio) interaction analysis of the wild-type and energy-minimized mutant structures.

Computational Predictions

DynaMut2 ΔΔG
-0.48kcal/mol
Destabilising — mild
AlphaMissense
0.106
LBen
AlphaFold pLDDT
26
model confidence
Schema
Cat 5
Category 5 — IDR Exclusion

Clinical Evidence

ClinVar classificationConflicting classifications of pathogenicity
Review statuscriteria provided, conflicting classifications
Associated conditionsAutosomal dominant nonsyndromic hearing loss 6 (DFNA6); Wolfram-like syndrome
InheritanceDocumented in association with DFNA6 (AD WFS1-related hearing loss) and Wolfram-like syndrome. Inheritance pattern uncertain given conflicting ClinVar classifications.
Population frequency (gnomAD v4)Ultra-rare · AF 0.0015%
cDNA changec.232G>A
ClinVar accessionVCV000903896
Last evaluated2025/05/19 00:00

Observed at very low frequency in gnomAD.

Structural Context

Position 78 sits in wolframin's N-terminal intrinsically disordered region (IDR), spanning residues 1–86. The pLDDT score of 26 indicates that AlphaFold's predicted geometry at this position is essentially unreliable — the structure shown in the model does not represent a single dominant conformation but rather an arbitrary picked sample from an ensemble.

The AlphaFold-derived neighbor analysis shows only PRO79 (2.5 Å) and THR77 (2.5 Å) — the immediate sequence neighbors and nothing else within 5 Å. This is itself a structural signature of IDR: in folded domains, every residue has multiple cross-chain neighbors at structural contact distance. In IDRs, only sequence neighbors appear because the chain has no consistent tertiary structure.

The DynaMut2 |ΔΔG| of 0.48 kcal/mol is therefore not trustworthy as a quantitative claim about the variant's structural impact. DynaMut2 assumes a meaningful input fold; IDR positions violate that assumption.

What is more revealing is the AlphaMissense score of 0.106 — well below the 0.564 likely-pathogenic threshold. AlphaMissense considers this variant likely benign. And yet ClinVar carries conflicting classifications including documented Wolfram-related conditions. The disconnect suggests either: (a) the variant is genuinely benign and clinical reports represent false-positive pathogenic calls or population-stratification artifacts; (b) the variant is pathogenic by a mechanism (e.g., IDR-mediated phase separation, partner binding through disordered region) that AlphaMissense's training does not capture; or (c) the variant's pathogenicity depends on context (e.g., compound heterozygosity with another WFS1 variant) that single-variant analysis cannot resolve.

None of these can be settled from the structural data alone.

Amino-acid chemistry
Glycine (G) → Arginine (R) — the smallest amino acid (backbone-only) replaced by a large, positively-charged guanidinium-bearing residue. Major chemistry shift, but the structural consequence depends on the local fold — and in an IDR, there is no well-defined local fold to disrupt.
Position in the protein
N-terminal intrinsically disordered region (residues 1–86) · position 78 sits in a region with pLDDT 26, deep in IDR territory. The AlphaFold model is not predictive in this region; the protein adopts an ensemble of conformations rather than a single fold.

Druggability Assessment

Category 5 — IDR Exclusion. pLDDT = 26 places this variant deep in the intrinsically disordered region of wolframin. DynaMut2 stability predictions are not trustworthy in this region. AlphaMissense's score of 0.106 (likely benign) further questions the variant's pathogenic mechanism.

The Atlas explicitly routes Category 5 variants away from computational drug discovery and toward wet-lab characterization. Recommended next steps: (1) confirm clinical penetrance with additional case data; (2) characterize the IDR's role in wolframin partner interactions experimentally; (3) test the variant in cell-based functional assays before drawing therapeutic conclusions.

Until experimental data clarifies the mechanism, this variant should NOT drive therapeutic strategy.

Why this matters

G78R demonstrates the value of the Atlas's Category 5 IDR exclusion. The conflicting clinical classifications + low AlphaMissense score + deep IDR location together flag the variant as one where the standard computational pipeline cannot reliably characterize pathogenicity. Pre-atlas drug discovery might have treated this position the same as any other Wolfram-spectrum variant. The Atlas surfaces the appropriate caution — Cat 5, wet-lab first, no computational drug design until the mechanism is clarified.
Therapeutic Strategy Handoff · prediction

Feed this card to Wolfram Intelligence

Download the G78R PDF below and upload it to Wolfram Intelligence to generate therapeutic-strategy proposals — guanidinium mimetics, sigma-1 agonist docking, NAC thiol-capping. NAC is already on the bench-testing list.

Download G78R PDF card ↓Strategies are AI-generated predictions, not validated therapeutics.

UniProt Domain Annotation

Chain1890 · Wolframin
Region1321 · Interaction with ATP6V1A
Region186 · Disordered